<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			var a = 1000;
			function(){
				console.log(a);
				if(false){
					var a = 'ni hao';
				}
			}
			f();	//undefined
		</script>
	</body>
</html>
